Celebrity "Sin": Arnold Schwarzenegger had an affair with his housekeeper and he had a child with her which he hid from his family.
http://www.eonline.com/news/arnold_schwarzenegger_housekeeper/242601

Celebrity Background: He was an Austrian American Body-Builder, actor, model, businessman, and currently a politician. He retired from his body-building career and stopped acting. He acted in movies such as 'Kindergarten Cop' and 'The Terminator'. He then replaced California Governor Gray Davis and finished his term. After that he was re-elected in 2007 to be the Governor of California again.
http://en.wikipedia.org/wiki/Arnold_Schwarzenegger

Backlash: People started to question him having been the Governor of California. When they find out he has fathered a child out of wedlock they feel betrayed. Keeping it from the public was just as bad as keeping it from his family. They wonder if this would have affected whether or not he was Governor.
http://www.usnews.com/opinion/blogs/leslie-marshall/2011/05/18/questions-about-the-arnold-schwarzenegger-scandal

Public Perception: People thought that he shouldn't have kept the secret from them and his family, it wasn't fair to anyone.

Repercussions: This scandal doesn't seem to have a negative affect his acting career. He is going to be in a new movie they are filming, and an animated TV series called The Governator. It hasn't affected the sales and his producer says it won't affect the movie.
http://www.hollywoodreporter.com/news/arnold-schwarzenegger-scandal-impact-his-189237

Aftermath: Arnold's children have suffered a lot from his mistakes. People begin to look down on them and think less of them as a whole family. Arnold and his wife separated shortly after the scandal which made it even harder on all four of their children.
http://akronnewsnow.com/news/national-news/item/528-schwarzenegger-s-daughter-scandal-aftermath-has-been-a-difficult-time

Extra Important Info:
http://topics.nytimes.com/top/reference/timestopics/people/s/arnold_schwarzenegger/index.html